AWS API Gateway currently limits log events to 1 KiB. Log events larger than 1024 bytes, such as request and response bodies,will be truncated by AWS API Gateway before submission to CloudWatch Logs. Thus for large request bodies undergoing template transformation before being forwarded to the http integration backend, debugging a faulty transform becomes guesswork if the error location is within the truncated portion. This tool aims to provide the full transform output by mimicking how AWS API Gateway transforms a JSON-formated request/response body with the Integration Request/Response Method's mapping template.
- Indicating error-causing line number within a mapping template if transform fails.
- Checks for malformed JSON - highlights which line and where.
- Checks for duplicate properties within generated JSON.
- Provides a well formatted JSON output.
*Note: Not all AWS Mapping Template built-in functions and variables are currently supported.
| Built-in Functions | Description | Supported |
|---|---|---|
| $input.json(x) | Evaluates a JSONPath expression and returns the results as a JSON string. | yes |
| $input.path(x) | Takes a JSONPath expression string (x) and returns an object representation of the result. | yes |
| $util.base64Encode() | Encodes the data into a base64-encoded string. | yes |
| $util.base64Decode() | Decodes the data from a base64-encoded string. | yes |
| $util.escapeJavaScript() | Escapes the characters in a string using JavaScript string rules. | yes |
Java 1.8 or greater.
- src/main/resources
- sample.json : request/response JSON-formatted body.
- testtemplate.vm : Gateway Mapping template.
Velson comes with Gradle Wrapper to avoid the need for managing distributions. To see the available tasks one can execute with the wrapper, run the following within the root project folder: ./gradlew tasks.
Windows use: gradlew or gradlew.bat instead as the command
- Clone the project.
- Building:
./gradlew assemble - Running:
./gradlew run - Testing:
./gradlew test
If using a text editor like Atom or Visual Studio Code, there are plugins/packages that make it easy to execute these commands without resorting to the terminal. See:
- build-gradle (Atom)
- gradle (Visual Studio Code)
- Generate the project:
./gradlew eclipse - Open Eclipse with the parent directory of the velson project as its workspace.
- Use Eclipse's Import Project menu to load the project as existing Gradle Project